When any notice or information is required to be given under ORS chapters 111, 112, 113, 114, 115, 116 and 117, a guardian, a guardian ad litem, a conservator or a person who is neither incompetent nor a minor may waive notice by a writing signed by the guardian, guardian at litem, conservator or person or the attorney of the guardian, guardian ad litem, conservator or person and filed in the proceeding, or by the appearance of the guardian, guardian ad litem, conservator or person at the hearing.
ORS 111.225